Hypertension (HTN) is one of the most prominent risk factors for cardiovascular diseases such as coronary artery disease and congestive heart failure. It is classically associated with hypertensive heart disease (HHD), which has as its hallmarks diastolic dysfunction, cardiac hypertrophy, and myocardial fibrosis. B-type natriuretic peptide (BNP) is a cardiac hormone which controls intravascular volume and arterial pressure to maintain the integrity of circulation. In addition to its diuretic and vasodilatory properties, both of which serve to lower blood pressure, BNP also has direct myocardial tissue effects. Indeed, BNP has anti-fibrotic and anti-hypertrophic properties, which make it a potentially attractive therapeutic for HHD. However, use of BNP for chronic therapy has been limited by its short in vivo half-life. Moreover, due to limited long-term BNP delivery strategies, the influence of continuous BNP treatment on the cardiovascular system and on the heart its self remains elusive. Our recent finding of reduced BNP activation in early stages of human HTN suggests that an impaired BNP system has a role in the development of HTN and its co-morbidities such as HHD. Our central hypothesis is that chronic cardiac BNP over-expression by AAV9-vector-mediated technology in HTN animals ameliorates the development of HHD. The overall goal of this proposal is to advance the biology and therapeutics of BNP, with a specific focus on the influence of vector-mediated chronic cardiac BNP over-expression on cardiac structure and function, especially on the development of HHD. Our specific aims are i) to evaluate the safety and pharmacokinetics/dynamics of AAV9 vector-mediated cardiac gene transfer, ii) to evaluate novel strategies to self-regulate production and release of BNP in vivo, and iii) to evaluate the therapeutic effects of chronic cardiac BNP delivery in an in vivo model of HHD with diastolic dysfunction and hypertrophy. Accomplishing the specific aims outlined in this proposal will lead to an innovative gene transfer vector strategy that would allow long-term cardiac BNP delivery in the hypertensive heart with diastolic dysfunction and hypertrophy. Our BNP delivery strategy may establish a novel chronic BNP therapy for severe HHD induced by resistant or malignant HTN, ultimately leading to prevention of heart failure.